In the case an infusion is carried out on a patient, or for similar occasions, an indwelling needle connected to an infusion line is made to puncture a blood vessel and indwell within the blood vessel.
Such an indwelling needle includes a hollow outer needle, an outer needle hub secured to a base (proximal end) of the outer needle, a stylet having a sharp needlepoint at its tip (distal end) which is inserted into the outer needle, and a stylet hub secured to the base of the stylet (refer, for example, to Japanese Laid-Open Patent Publication No. 10-179734).
At the time of making the indwelling needle puncture the patient's blood vessel, the stylet is inserted into the outer needle, while the needlepoint of the stylet protrudes from the tip of the outer needle. In such an assembled condition, a puncturing operation is carried out, wherein normally, the outer needle hub is connected to a connector of the infusion line.
Then, when the needlepoint of the stylet has reached the inside of the blood vessel, blood flowing through the opening at the needlepoint passes through the inner cavity of the stylet, and flows into an interior region of the transparent stylet hub (flashback). This makes it possible to confirm (visually check) that the blood vessel has been accessed by the stylet.
After confirmation of flashback, the outer needle is advanced as a guiding stylet, so as to insert the outer needle into the blood vessel (to achieve puncture).
Next, while gripping the outer needle by hand, the stylet is pulled out of the outer needle. Then, an infusion liquid is infused through the connected infusion line and the outer needle.
Meanwhile, the outer needle hub is provided with vanes as an operating part thereof. When the stylet and the outer needle are made to puncture the living body, the indwelling needle assembly is placed in an assembled condition, and a puncturing operation is carried out on the skin while pinching the vanes with the fingers.
However, the indwelling needle assembly described in Patent Document 1 has a problem in that, at the time the puncturing operation is performed, the stylet may be pushed back by the skin before the skin is punctured and retracted into the outer needle, i.e., operability of the puncturing operation may be poor.